PROJECT SUMMARY/ABSTRACT This proposal describes a five-year career development program for Dr. Roland S. Wu in the role of principal investigator. Dr. Wu is an Assistant Clinical Professor at the Cardiovascular Research Institute and the Division of Cardiology, Department of Internal Medicine at University of California San Francisco. This work will focus on gene regulation in cardiac regeneration and will build upon Dr. Wu?s background in cardiac development and genetic models of cardiovascular disease. His objective is to determine the mechanisms underlying the endocardial response to cardiac injury and endocardial support of cardiac regeneration. In this career development plan, Dr. Brian Black, an expert in cardiovascular development and gene regulation, will provide the principal guidance for Dr. Wu?s work. Additional mentorship will be provided by a group of world-class experts that include leaders in cardiac regeneration (consultant Kenneth Poss, Duke), translational medicine (advisor Deepak Srivastava, UCSF), and computational biology (advisor Katherine Pollard, UCSF). The environment at UCSF is outstanding with leading experts in a variety of fields. Dr. Wu?s training plan includes focused tutorials and didactic coursework participation and presentation at conferences and mentored guidance with manuscript and grant preparation. Dr. Wu?s proposal aims to study gene regulation in endocardium as it responds to injury in cardiac regeneration. He approaches this through a combination of powerful and novel techniques: 1) an enhancer barcoding system for rapid enhancer identification, and 2) a rapid genetic editing pipeline for genetic screening. Aim 1 identifies and characterizes endocardial enhancers responsive to cardiac injury and regeneration. Aim 2 defines the transcriptional networks involved in endocardial gene regulation and the endocardial response to cardiac injury and regeneration. This work will make use of high throughput and detailed transgenic analyses in the zebrafish and in the mouse, taking advantage of the strengths of each system. Additionally, this work will use molecular biology and bioinformatics approaches to predict key regulatory elements in regeneration enhancers, and those predictions will be validated in zebrafish and mouse assays. Dr. Wu?s Career Development Award proposal comprises a promising candidate, impactful scientific investigation, world-class mentorship, and a rigorous training plan in an outstanding environment. The results of this work provide: 1) immediate new biological insights that directly address causality, and 2) a foundation for long-term independent program to dissect the mechanisms regulating cardiac regeneration and the cardiac response to injury. This work will provide a foundation for Dr. Roland Wu?s work as an independent investigator.